TRANSACTIONS OF SECTION C. 551 



Tlie petrology of the main masses has been partially treated, but more infor- 

 mation is needed, and the dykes and yeins are undescribed. They are interesting 

 and varied. Among them is true mica trap. 



The physical geology has been admirably treated by Ansted. 



The islands offer a held for the investigation of the distinctive characteristics 

 of dykes, veins, &c., and the study of archsean rocks. 



The proper investigation requires a resident. 



2. Notes on Alpine Post-Oarbonifermis (^Dt/assic) and Triassic Geology. By 

 the Rev. A. Irving, B.Sc, B.A., F.G.S. 



This paper is intended to call the attention of English geologists to the most 

 recent results obtained in Alpine geology by such observers as Giimbel, Von Hauer, 

 Mojsisovics, Theobald, Zittel, and Pichler (not to mention others), and so to sup- 

 plement the author's papers recently published in the ' Geological Magazine ' on the 

 Post-carboniferous and Triassic systems. Some recent observations by the author 

 of the paper are also contained herein. 



Of the Post-carboniferous (Dyassic) system, observation so far has failed to 

 detect the presence of any deposits on the north side of the crystalline axis of the 

 Alpine chain ; the triassic strata rest at once upon metamorphosed rocks of Silurian 

 age (Von Hauer). On the south side the principal deposits are comprehended 

 imder the term Ven-ucano (grey and red-brown conglomerates and breccias, with 

 red sandstones, and occasional thin beds of lignite or coal). Views as to the 

 true horizon of these beds are as yet divided ; Von Hauer refers them to the 

 lowest division of the Trias, at the same time admitting the propriety of Giimbel's 

 view, that they may be the equivalents of the Rothliegende of Germany. The 

 latter wiiter even considers that strata analogous to the Zechstein of Germany may 

 be recognised in the Alps. 



The enormous displaj' of volcanic activity recorded in the Rothliegende of 

 Germany is foimd repeated in the Alps in Post-carboniferous times. As an illus- 

 tration of this the author gives some observations made within the last few weeks 

 on the interstratification of ancient acid lava-flows (so-called porphyries) and 

 bedded volcanic ' ash ' of the Rittner Horn, one of the former centres of activity 

 which produced the ' porphyries ' of the Bozeu district, the most extensive known 

 in the world. The mountain is a true ' stratified cone,' preserving at its summit 

 about a half of its ancient crater-walls. It is a remarkable illustration of the pro- 

 priety of classifying the 'porphyries' among the 'Older Eruptive Rocks,' as 

 maintained some time ago by Creduer. 



Transition Beds. — Giimbel considers the dark BeUerophon-limeatonQ of the 

 Puster Thai, as well as the Griidner sandstone at Neumarkt, near Bozen, the 

 white Schwaz limestone in the Inn Thai, and some other deposits to be properly 

 placed here, though others woidd place them in the Dyas. Their organic remains, 

 he remarks, do not give them ' a pure Dyassic character, but very much more that 

 of a transition series from the Dyas to the Trias ' (vide Anleitung zu geologischen 

 Beohachtungen in den Alpen). 



Alpine Trias. — Sections of these deposits — one on the north slope, through the 

 Steinernes Meer, near Saalfelden (after Mojsisovics) — another on the south across 

 the valley of St. Gassian (taken by the author within the last few weeks), are 

 described, and their correlation pointed out, in order to illustrate the completeness 

 of the Triassic system as developed in the Alps, the clear sequence which has been 

 established among its sub-formations, and the soundness therefore of the view 

 propounded by Professor Oredner, and quoted by the author in another place, that 

 the key to the true geological history of Triassic times is to be found in the 

 Alpine Trias. 



The importance of the views maintained by so high an authority as Professor 

 Giimbel as to the transition character of certain deposits is insisted xipon ; at the 

 same time hasty judgment, while awaiting (for a few years) the results of more 

 extended observations, is deprecated. 



